Bangladesh shares land borders with India to the west, north, and east, and Myanmar to the southeast; to the south it has a coastline along the Bay of Bengal. It is narrowly separated from Bhutan and Nepal by the Siliguri Corridor; and from China by the Indian state of Sikkim in the north. Dhaka, the capital and largest city, is the nation's political, financial and cultural centre. Chittagong, the second-largest city, is the busiest port on the Bay of Bengal. The official language is Bengali.